[PATCH] D150855: MachineCombiner: consider all uses in getLatency()

[Sergei Barannikov via Phabricator via llvm-commits]

barannikov88 added a comment.

Shouldn't there be any test changes?
I'm not familiar with this pass and can't help with further review.



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Comment at: llvm/lib/CodeGen/MachineCombiner.cpp:286
+            NewRoot, NewRoot->findRegisterDefOperandIdx(MO.getReg()), &UseInstr,
+            UseInstr.findRegisterUseOperandIdx(MO.getReg()));
+      } else {
----------------
(Assuming iterating over all uses is necessary.)
If the register is used by a single instruction multiple times, `findRegisterUseOperandIdx` will always find the first use.
I think `UseMO : MRI->use_[nodbg_]operands(MO.getReg())` should be used instead in the `for` loop, and `UseMO.getOperandNo()` here.



Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D150855/new/

https://reviews.llvm.org/D150855